Patent risks of open source software
Using open source software offers various advantages, such as the ability to reduce costs and development time, or to avoid being dependent on a single vendor. The use of open source software also has presents some risks. One of these risks is that you may have to grant a royalty-free patent license when distributing open source software implementing your own patented technology. There is also the distinct possibility that some open source software may infringe on third party patents.
To reduce these risks, the license conditions of all open source software should be carefully evaluated. Open source software should be screened for patent risks before use and/or distribution. The chance that a particular open source software package infringes on a software patent is quite real.
Furthermore it is recommended to compare the open source software with the own patent portfolio. If there is a chance that an own patent is incorporated in an open source software package, then the use of that software package should be avoided.
Patent and open source software are fundamentally incompatible. The basis of the open source software development model is the sharing of source code and the right to use other people's code in one's own work. If that code infringes on a patent, distribution and use is not allowed without permission from the patent holder.
Software patents considered trivial
The last ten years has seen a great increase in the number of patents on software-related inventions. Because the criteria for novelty and inventive step are a lot easier to fulfill than many programmers expect, the general opinion regarding patents in the open source community is rather negative. The term "software patent" appears to be almost a synonym for "triviality".
Furthermore, many in the open source community, in particular in Europe, consider software patents to be invalid by definition, because the European Patent Convention excludes patents on programs for computers as such. Current case law of the Board of Appeals of the European Patent Office which permits patents on software if there is a "technical effect" is usually ignored or considered to be contrary to the spirit of the European Patent Convention.
Avoiding software patents
In case of copyright problems it is always possible to replace an infringing program by an independently created implementation with similar functionality. According to patent law this independent implementation also constitutes infringement. This makes it impossible in many cases to implement certain functionality without infringing on a patent, which means that the software cannot be distributed and used according to the open source principles.
Although theoretically possible, in practice it is often not or hardly possible to avoid infringing on a patent. Working around the patent by choosing an alternative technology is often not an option, for example because the patent covers the de facto standard for a certain file format or communication protocol. And furthermore software patents often appear to be of such a fundamental nature that working around them is often simply not possible.
Because of these reasons, patents are not exactly popular in the open source community. The supporters of the Free Software Foundation in particular pursue a very active lobby against software patents.
Because of the large number of potentially relevant patents and their putative triviality, many authors of open source software do not pay any attention to patents when writing their software. The chance that a particular piece of open source software infringes on some patent is therefore quite real.
A patent holder can make life very difficult for the author of an open source software package. Of course this also holds for authors of commercial software, but an open source author usually does not have the means to take a license for all users of his software and does not have his own patent portfolio to improve his bargaining position. The free availability of the source code of course makes proving infringement very easy. However, it does not happen very often that a patent holder approaches the author himself. Distributors of CD-ROMs with open source software regularly face claims from patent holders. Such distribution of infringing software usually at the very least counts as indirect infringement. A recent example is the Linux distributor Red Hat which has removed all MP3 software from its distribution because of potential conflicts with the MP3 licensing program of the Fraunhofer Institute and Thomson multimedia.
Users of infringing open source software of course can also be approached by the patent holder. This is mainly a risk if the open source software has been incorporated in an expensive product or service, for example as part of the operating system of a digital television or as part of the content management system for an online newspaper.
The use of open source software can also introduce risks for patent holders themselves. Some open source software licenses contain provisions aimed at reducing the risks of patents for authors and users of the software. If a patent holder distributes open source software under such a license, he may be forced to grant a royalty-free license or a non-assert declaration to all users of this software.
Patent licenses under the Mozilla Public License
For example, anyone who contributes to a project licensed under the Mozilla Public License is required to give an unlimited, royalty-free patent license on his contribution to the whole world. Users of software under this license can only assert patents they have on this software against the author(s) or other users if they also pay a reasonable royalty for their past use of the software. If no agreement can be reached on what constitutes "reasonable", the license agreement terminates retroactively.
Patent licenses under the GNU General Public License
The GNU General Public License (GPL) forbids imposing any restriction whatsoever on the rights granted by the license to the recipients of the software. If a distributor does impose any further restrictions, his license under the GPL is canceled. This means that a patent holder who distributes a software package incorporating his patent can no longer assert that patent against people who distribute that package further or incorporate the package in their own product. Asserting a patent restricts the rights granted by the GPL and therefore is not permitted. This means that a competitor is now free to incorporate that package in his own product without having to pay any royalty to the patent holder. Of course that part of the product (and all other parts based on that part) will have to be made available under the GPL.
It does not matter whether the patent covers a contribution that the patent holder made to the software or the original version developed by someone else. The mere distribution in unmodified form of third party software under the GPL means that any patent covering that software becomes unenforceable.
Patent licenses under the GNU Library/Lesser General Public License
The Library GPL contains a comparable provision, but restricted to patents covering the library itself. Patents that cover an application using the library do not have to be licensed freely.
This does not mean there are no patent risks associated with the LGPL. A library under this license could still implement one of your own patents. This patent then still has to be licensed on a royalty-free basis, even when the library is not modified or distributed as a separate file.